CA1288203C - Method of decreasing black liquor viscosity - Google Patents
Method of decreasing black liquor viscosityInfo
- Publication number
- CA1288203C CA1288203C CA000524062A CA524062A CA1288203C CA 1288203 C CA1288203 C CA 1288203C CA 000524062 A CA000524062 A CA 000524062A CA 524062 A CA524062 A CA 524062A CA 1288203 C CA1288203 C CA 1288203C
- Authority
- CA
- Canada
- Prior art keywords
- black liquor
- liquor
- temperature
- viscosity
- decreasing
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
Classifications
-
- D—TEXTILES; PAPER
- D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
- D21C—PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21C11/00—Regeneration of pulp liquors or effluent waste waters
- D21C11/04—Regeneration of pulp liquors or effluent waste waters of alkali lye
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S159/00—Concentrating evaporators
- Y10S159/08—Multieffect or multistage
Landscapes
- Paper (AREA)
- Compounds Of Unknown Constitution (AREA)
Abstract
ABSTRACT
METHOD OF DECREASING BLACK LIQUOR VISCOSITY
A method for decreasing the viscosity and improving the evaporability of a sulfate liquor from a cellulose cook. The temperature of the black liquor is raised above the cooking temperature, preferably to 170 - 190°C for splitting the macro-molecular fraction contained in the liquor. Na2S or any other reducing agent intensifies the splitting.
METHOD OF DECREASING BLACK LIQUOR VISCOSITY
A method for decreasing the viscosity and improving the evaporability of a sulfate liquor from a cellulose cook. The temperature of the black liquor is raised above the cooking temperature, preferably to 170 - 190°C for splitting the macro-molecular fraction contained in the liquor. Na2S or any other reducing agent intensifies the splitting.
Description
*~
~ _ _ . . . .
hf~ irr~;~tion relates tO L~ mel IIGCI 0~ rech;~;rc~ the viscosi y ~n~ l~f i~provil~g the evaporability ol blac~ liquor from a cellulose cook.
~hen evaporating sulphate black liquc)r to a high ~rO ~ 7~ ~) dry-solids content, the viscosity Gf the liquor increases rapidly. At the same time its evaporability decreases remarkab]y as the black liquor sticks to the heat surfaces thus impairing the heat transfer from the heat surfaces to the black liquor, whih results in a decrease in the efficiency o the evaporator. It may also result in overheating of ~he heat transfer surfaces. With high dry-solids contents the flow e~ocity, for example, on the heat transfer surfaces of 2 falling-iilm evaporator decreases and in the end the sticky black liquor prevents the fl ow through the evapora or.
It is advantageous to evaporate the liquor so as to have an as high dry-solids content as possible for further treatment, the effective combustion value of the waste liquor is then higher than that of a wet liquor and the volume of the steam generated by the recovery boiler is respectively greater.
Background Art:
Swedish patent specification no. SE 8400904 discloses a method of decreasing the viscosity of black liquor after the evaporator immediately hefore the revocery boiler by oxidizing the liquor wherein after liquor of a higher dry-solids content can be introduced into the boiler. The oxidation reaction which is achieved by mixing warm oxidizing gas (such as air!
in the liquor raises the temperature of the liquor and makes it more fluent or flowable. The method requires quite a complex apparatus for distributing the oxidizing gas evenly in 0;~
ne the LeCoV~ry l)(.i It~,- W}~ r-i~ ir t~e ier~peratl1re o~
n~ F)~ E>ir~l facili-tatf~J. :ir t~ t}~
is appliecl in the ~r(,(~ss helore the final evaporatior, t~e carboll dioxide and organi~ acids produced in the oxidizirc reaction rec11]ce thc p~ of the liquor which mai~ result ln ~olldensation of the lignin and ca~7se considerah1e depositions on tlle heat transfer suLfaces.
It is a know fact that the visco~ity of black liquor depends on the amount of the macro-molecular lionin in the liquor. In prior art methods the viscosity has been decreased b-i remc~ing the macro-molecular fraction.
Finnish patent specification no. 66035 discloses a method o-removing organic material containing a macro-molecular fraction from the effluent of a cellulose cook. According to this method the macro-molecular fraction is removed by ultra-filtering of precipitating. Precipitation is performed by oxidi,ing the effluent which significantly reduces the viscosity of the effluent.
The ultrafiltering method, by which the macro-molecular fraction is separated from the effluent, requires, however, sizable and expensive apparatus. A complex apparatus is required for the precipitation. Addition of chemicals in the precipitation phase affects the chemical balance oF the whole system. In continuous operation, separation of the chemicals is problematic and cannot easily be controlled or changed.
Disclosure of Invention:
The object of the present invention is to eliminate or minimise the above disadvantages and to provide a methGd 'or decreacing the viscosity of black liquor before final evaporation without separation of the different fractions of a2(1~
the hlilc~ uo~- wllicil would then h~ve to } e treat--sepal-ately.
~he main ch.lracteristic Leature of ~he method Or the present invelltioll is that the temperature of the black liquor is raised ~ove the cooking temperature, preferably up to 170 -190C, in order to sp]it the macro-molecular lignin fractions.
The method according to the invention provides for a controlled reduction of the viscosity of the whole black liquor amount - without the problematic separation of different fractions - without e~tensive investments both in batch and continuous cooking.
With the method according to the present invention the capacity of an existing evaporation plant can be impro-ved or in a new evaporation plant, the heat surface of the con-centrator can be dimensioned smaller. Further, the final dry-solids content of the liquor can be increased without any substantial changes in the pressurization or the apparatus, which improves the heat economy of the combustion. When the flow resistance decreases the pumpability of the liauor improves and the power consumption of the pump decreases.
When studying the absolute amounts of lignin fractions of different size as a function of cooking parameters in a soda cook and in a sulfate cook the following conclutions can be reached:
- in a soda cook the absolute amount of macro-molucular lignin increases at the beginning and after that maintains a constant level ~, sul(~lt~ ook tl~e i~moun~ of Inacro mo1ecu1ar ]i~nir~
i1lcl~eases ~t the be(rinninq ~In~l r~ <; th~ m~i~imum ~fter ~/hic~
tlle clm~ t c~ a1ly ~re~ses as the Sll~ f`ide .splits the lignin as S}10WIl ill the fOllC)~ rlg t~ble.
Sulfidity Cooking time M > 10000 M > 5000 min % g/kg dry solids ~ g/kg dry solids lQ 36,4 ll 23,4 930,0 20 66,7 110 932,1 22 78,4 170 725,1 22 78,8 1~0 1241,1 29 96,0 170 1034,5 22 75,9 0 10 79,6 18 24,7 0 110 1440,2 32 91,9 0 170 1752,5 33 101,8 When the sulfidity is 35 % the macro-molecular fraction (M >
10000) 25,1 g/kg dry solids has decreased after a cooking time of 170 min; after 110 min the fraction was 32,1 g/kg dry solids. When the sulfidity is 25 ~ the amount of the macro-molecular fraction has-decreased with the time. When the sulfidity is zero no splitting of molecules can be seen.
Thus, in order to secure good results, oxidation has to be prevented to preserve the sulfur in the sulfide state.
The higher the sulfidity of the cook is the more intensive the splitting is. In normal cooking in the sulfidity range of 20 - 35 % the remaining sulfide volume is adequate for the splitting. A reducing agent such as sulfur or polysulrlde can in some cases be added to intensify the splitting.
1~8~03 ~t ~as surp~ ingly l<~ln(~ t- that raisinq the temr~eratllr~
clb<~ -` t]lc i~rma~ c~okinq temperature, to ]7~ 0 (, accelerates the spl-itlin(J of the macrr-~G1uc~1ar lignirl fract;~n to the e~1ellt that only 1 - 5 minutes in a raise(?
temperature ls adequate to cause a decrease in the splitting and the viscoslty. lt was a~so founrl out that compounds of Ca and lignin causing deposition in the evaporator are dispersed during the heat treatment.
As described above, the viscosity can be decreased in the black liquor itself without addition of chemicals or separation either during the cooking or the evaporation process by simple pressure heating. The temperature can be raised also in a separate circulation loop connected to the cooking process in continuous cooking in particular.
In each case the most economical heating method is chosen, for instance, direct or indirect steam heating or electric heating.
rief descriPtion of Drawing:
The figure indicates the effect of heat treatment on black liquor viscosity. Black liquor samples having a dry-solids content of 65 %, 70 %, 75 % and 80 % were treated at 190C.
Viscosity was measured before the treatment, after 1 min, 5 min and 60 min. For instance, after a treatment of 60 min, the viscosity of the liquor having a dry-solids content of 70 - 73 % had decreased to the same level as the viscosity of an untreated liquor having a dry-solids content of 65 ~ which is the level of normal combustion liquid.
Mode for Carrying out the Invention:
~ . _ The effect of further heating of mill liquor on the viscosity of the liquor is indicated by the following measurement results. Also the effect of Na2S or NaOH addition has been '-' ' lx~a~o~
onc;idel~d. The material teste~l was l)'~lck li~ r fro~ a K~nl~r~ estioll havin~ ~I dry-soli~s cGntent of 71 %.
Chemical added Heatinq TemperatureViscosity min. C mPas Untreated liquor 2r)o - 1 190 7~
- ~0 190 40 Na2S 60 120 158 Na2S 60 190 32 NaOH 20 190 63 NaOH 60 190 52 The effect of heat treatment on the viscosity is thus obvious.
A treatment at 120C decreases viscosity but not even nearly as efficiently as a treatment at 190C. A heat treatment of only one minute at 190C decreases the viscosity from 200 mPas to 78 mPas. Addition of Na2S seems to have a slight de-creasing effect on the viscosity, addision of NaOH on the other hand no effect at all.
Industrial Applicability:
The present invention thus provides a method for decreasing the viscosity in order to improve the evaporability and liquor transfer. The invention can be modified within the scope of protection defined by the patent claims.
~ _ _ . . . .
hf~ irr~;~tion relates tO L~ mel IIGCI 0~ rech;~;rc~ the viscosi y ~n~ l~f i~provil~g the evaporability ol blac~ liquor from a cellulose cook.
~hen evaporating sulphate black liquc)r to a high ~rO ~ 7~ ~) dry-solids content, the viscosity Gf the liquor increases rapidly. At the same time its evaporability decreases remarkab]y as the black liquor sticks to the heat surfaces thus impairing the heat transfer from the heat surfaces to the black liquor, whih results in a decrease in the efficiency o the evaporator. It may also result in overheating of ~he heat transfer surfaces. With high dry-solids contents the flow e~ocity, for example, on the heat transfer surfaces of 2 falling-iilm evaporator decreases and in the end the sticky black liquor prevents the fl ow through the evapora or.
It is advantageous to evaporate the liquor so as to have an as high dry-solids content as possible for further treatment, the effective combustion value of the waste liquor is then higher than that of a wet liquor and the volume of the steam generated by the recovery boiler is respectively greater.
Background Art:
Swedish patent specification no. SE 8400904 discloses a method of decreasing the viscosity of black liquor after the evaporator immediately hefore the revocery boiler by oxidizing the liquor wherein after liquor of a higher dry-solids content can be introduced into the boiler. The oxidation reaction which is achieved by mixing warm oxidizing gas (such as air!
in the liquor raises the temperature of the liquor and makes it more fluent or flowable. The method requires quite a complex apparatus for distributing the oxidizing gas evenly in 0;~
ne the LeCoV~ry l)(.i It~,- W}~ r-i~ ir t~e ier~peratl1re o~
n~ F)~ E>ir~l facili-tatf~J. :ir t~ t}~
is appliecl in the ~r(,(~ss helore the final evaporatior, t~e carboll dioxide and organi~ acids produced in the oxidizirc reaction rec11]ce thc p~ of the liquor which mai~ result ln ~olldensation of the lignin and ca~7se considerah1e depositions on tlle heat transfer suLfaces.
It is a know fact that the visco~ity of black liquor depends on the amount of the macro-molecular lionin in the liquor. In prior art methods the viscosity has been decreased b-i remc~ing the macro-molecular fraction.
Finnish patent specification no. 66035 discloses a method o-removing organic material containing a macro-molecular fraction from the effluent of a cellulose cook. According to this method the macro-molecular fraction is removed by ultra-filtering of precipitating. Precipitation is performed by oxidi,ing the effluent which significantly reduces the viscosity of the effluent.
The ultrafiltering method, by which the macro-molecular fraction is separated from the effluent, requires, however, sizable and expensive apparatus. A complex apparatus is required for the precipitation. Addition of chemicals in the precipitation phase affects the chemical balance oF the whole system. In continuous operation, separation of the chemicals is problematic and cannot easily be controlled or changed.
Disclosure of Invention:
The object of the present invention is to eliminate or minimise the above disadvantages and to provide a methGd 'or decreacing the viscosity of black liquor before final evaporation without separation of the different fractions of a2(1~
the hlilc~ uo~- wllicil would then h~ve to } e treat--sepal-ately.
~he main ch.lracteristic Leature of ~he method Or the present invelltioll is that the temperature of the black liquor is raised ~ove the cooking temperature, preferably up to 170 -190C, in order to sp]it the macro-molecular lignin fractions.
The method according to the invention provides for a controlled reduction of the viscosity of the whole black liquor amount - without the problematic separation of different fractions - without e~tensive investments both in batch and continuous cooking.
With the method according to the present invention the capacity of an existing evaporation plant can be impro-ved or in a new evaporation plant, the heat surface of the con-centrator can be dimensioned smaller. Further, the final dry-solids content of the liquor can be increased without any substantial changes in the pressurization or the apparatus, which improves the heat economy of the combustion. When the flow resistance decreases the pumpability of the liauor improves and the power consumption of the pump decreases.
When studying the absolute amounts of lignin fractions of different size as a function of cooking parameters in a soda cook and in a sulfate cook the following conclutions can be reached:
- in a soda cook the absolute amount of macro-molucular lignin increases at the beginning and after that maintains a constant level ~, sul(~lt~ ook tl~e i~moun~ of Inacro mo1ecu1ar ]i~nir~
i1lcl~eases ~t the be(rinninq ~In~l r~ <; th~ m~i~imum ~fter ~/hic~
tlle clm~ t c~ a1ly ~re~ses as the Sll~ f`ide .splits the lignin as S}10WIl ill the fOllC)~ rlg t~ble.
Sulfidity Cooking time M > 10000 M > 5000 min % g/kg dry solids ~ g/kg dry solids lQ 36,4 ll 23,4 930,0 20 66,7 110 932,1 22 78,4 170 725,1 22 78,8 1~0 1241,1 29 96,0 170 1034,5 22 75,9 0 10 79,6 18 24,7 0 110 1440,2 32 91,9 0 170 1752,5 33 101,8 When the sulfidity is 35 % the macro-molecular fraction (M >
10000) 25,1 g/kg dry solids has decreased after a cooking time of 170 min; after 110 min the fraction was 32,1 g/kg dry solids. When the sulfidity is 25 ~ the amount of the macro-molecular fraction has-decreased with the time. When the sulfidity is zero no splitting of molecules can be seen.
Thus, in order to secure good results, oxidation has to be prevented to preserve the sulfur in the sulfide state.
The higher the sulfidity of the cook is the more intensive the splitting is. In normal cooking in the sulfidity range of 20 - 35 % the remaining sulfide volume is adequate for the splitting. A reducing agent such as sulfur or polysulrlde can in some cases be added to intensify the splitting.
1~8~03 ~t ~as surp~ ingly l<~ln(~ t- that raisinq the temr~eratllr~
clb<~ -` t]lc i~rma~ c~okinq temperature, to ]7~ 0 (, accelerates the spl-itlin(J of the macrr-~G1uc~1ar lignirl fract;~n to the e~1ellt that only 1 - 5 minutes in a raise(?
temperature ls adequate to cause a decrease in the splitting and the viscoslty. lt was a~so founrl out that compounds of Ca and lignin causing deposition in the evaporator are dispersed during the heat treatment.
As described above, the viscosity can be decreased in the black liquor itself without addition of chemicals or separation either during the cooking or the evaporation process by simple pressure heating. The temperature can be raised also in a separate circulation loop connected to the cooking process in continuous cooking in particular.
In each case the most economical heating method is chosen, for instance, direct or indirect steam heating or electric heating.
rief descriPtion of Drawing:
The figure indicates the effect of heat treatment on black liquor viscosity. Black liquor samples having a dry-solids content of 65 %, 70 %, 75 % and 80 % were treated at 190C.
Viscosity was measured before the treatment, after 1 min, 5 min and 60 min. For instance, after a treatment of 60 min, the viscosity of the liquor having a dry-solids content of 70 - 73 % had decreased to the same level as the viscosity of an untreated liquor having a dry-solids content of 65 ~ which is the level of normal combustion liquid.
Mode for Carrying out the Invention:
~ . _ The effect of further heating of mill liquor on the viscosity of the liquor is indicated by the following measurement results. Also the effect of Na2S or NaOH addition has been '-' ' lx~a~o~
onc;idel~d. The material teste~l was l)'~lck li~ r fro~ a K~nl~r~ estioll havin~ ~I dry-soli~s cGntent of 71 %.
Chemical added Heatinq TemperatureViscosity min. C mPas Untreated liquor 2r)o - 1 190 7~
- ~0 190 40 Na2S 60 120 158 Na2S 60 190 32 NaOH 20 190 63 NaOH 60 190 52 The effect of heat treatment on the viscosity is thus obvious.
A treatment at 120C decreases viscosity but not even nearly as efficiently as a treatment at 190C. A heat treatment of only one minute at 190C decreases the viscosity from 200 mPas to 78 mPas. Addition of Na2S seems to have a slight de-creasing effect on the viscosity, addision of NaOH on the other hand no effect at all.
Industrial Applicability:
The present invention thus provides a method for decreasing the viscosity in order to improve the evaporability and liquor transfer. The invention can be modified within the scope of protection defined by the patent claims.
Claims (5)
1. A method for decreasing the viscosity and improving the evaporability of sulfate black liquor from a cellulose pulp digester, consisting essentially of:
withdrawing said sulfate black liquor from said digester, raising the temperature by pressure heating said sulfate black liquor to a temperature above the cooking temperature prior to the final evaporation thereof, maintaining said black liquor at said raised temperature for 1-60 minutes so as to split the macro-molecular lignin fraction contained in said liquor, and thereafter, evaporating said black liquor.
withdrawing said sulfate black liquor from said digester, raising the temperature by pressure heating said sulfate black liquor to a temperature above the cooking temperature prior to the final evaporation thereof, maintaining said black liquor at said raised temperature for 1-60 minutes so as to split the macro-molecular lignin fraction contained in said liquor, and thereafter, evaporating said black liquor.
2. A method as claimed in claim 1, wherein the temperature of the black liquor is raised immediately after the cook.
3. A method as claimed in claim 1 or 2, wherein the temperature of the black liquor is raised immediately before the final evaporation.
4. A method as claimed in claim 1 or claim 2 wherein a reducing agent such as sulfur or polysulfide is added to the black liquor.
5. A method as claimed in claim 1 or claim 2, wherein the temperature of the black liquor is raised to 170-190°C.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FI854732 | 1985-11-29 | ||
| FI854732A FI75615C (en) | 1985-11-29 | 1985-11-29 | FOERFARANDE FOER SAENKNING AV SVARTLUTENS VISKOSITET. |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1288203C true CA1288203C (en) | 1991-09-03 |
Family
ID=8521769
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000524062A Expired - Lifetime CA1288203C (en) | 1985-11-29 | 1986-11-28 | Method of decreasing black liquor viscosity |
Country Status (12)
| Country | Link |
|---|---|
| US (1) | US4929307A (en) |
| JP (1) | JPS63502674A (en) |
| BR (1) | BR8607216A (en) |
| CA (1) | CA1288203C (en) |
| CS (1) | CS273179B2 (en) |
| FI (1) | FI75615C (en) |
| FR (1) | FR2593528B1 (en) |
| PL (1) | PL155015B1 (en) |
| PT (1) | PT83838B (en) |
| SE (1) | SE466756B (en) |
| SU (1) | SU1720498A3 (en) |
| WO (1) | WO1987003315A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101580285A (en) * | 2009-04-01 | 2009-11-18 | 兰州节能环保工程有限责任公司 | Thermal cracking device for papermaking black liquor of non-wood material |
Families Citing this family (18)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI85515C (en) * | 1990-07-09 | 1996-04-10 | Ahlstroem Oy | Process for controlling the sulphidity of a sulphate cellulose plant |
| FI87092C (en) * | 1990-11-07 | 1992-11-25 | Ahlstroem Oy | FOERFARANDE FOER BEHANDLING AV SVARTLUT |
| US5326433A (en) * | 1991-02-06 | 1994-07-05 | Ahlstrom Recovery Inc. | Multi-level sulfide content white liquor production and utilization in cellulose pulping |
| WO1992013994A1 (en) * | 1991-02-06 | 1992-08-20 | A. Ahlstrom Corporation | A method of recovering energy and chemicals from black liquor |
| FI92226B (en) * | 1991-04-15 | 1994-06-30 | Ahlstroem Oy | Method for concentrating waste liquor and recovering cooking chemicals in pulp production with alcohol-based cooking solutions |
| US5213662A (en) * | 1991-08-14 | 1993-05-25 | Kamyr, Inc. | Treatment of chips with high temperature black liquor to reduce black liquor viscosity |
| FI92725C (en) * | 1991-09-09 | 1994-12-27 | Ahlstroem Oy | Process for preparing boiling liquid |
| US5234546A (en) * | 1991-09-10 | 1993-08-10 | Kamyr, Inc. | Polysulfide production in white liquor |
| FI95822C (en) * | 1991-09-27 | 1996-03-25 | Ahlstroem Oy | Treatment of the melt of a soda boiler or equivalent boiler |
| US5360513A (en) * | 1992-02-13 | 1994-11-01 | A. Ahlstrom Corporation | Sulphur removal from gases associated with boilers having cascade evaporators |
| US5662774A (en) * | 1992-04-01 | 1997-09-02 | Tampella Power Oy | Adjusting the sulphur balance of a sulphate cellulose plant by heat treating black liquor in a last evaporation stage |
| US5489363A (en) * | 1993-05-04 | 1996-02-06 | Kamyr, Inc. | Pulping with low dissolved solids for improved pulp strength |
| US5472568A (en) * | 1993-09-07 | 1995-12-05 | Air Products And Chemicals, Inc. | Method for controlling the viscosity of Kraft black liquor |
| GB9503562D0 (en) * | 1995-02-23 | 1995-04-12 | Thor Technology Corp | Black liquor viscosity control |
| SE520956C2 (en) * | 2001-12-05 | 2003-09-16 | Kvaerner Pulping Tech | Continuous boiling with extra residence time for drained liquid outside the boiler |
| RU2567352C2 (en) * | 2010-07-07 | 2015-11-10 | Стора Энсо Ойй | Method for obtaining precipitated lignin from black liquor and precipitated lignin obtained thereof |
| JP7280563B2 (en) * | 2017-06-30 | 2023-05-24 | 株式会社片山化学工業研究所 | Viscosity reducer composition and black liquor concentration method |
| JP7317509B2 (en) * | 2019-01-10 | 2023-07-31 | 日本製紙株式会社 | Method for producing lignin, and lignin-based dispersant |
Family Cites Families (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1719130A (en) * | 1925-12-16 | 1929-07-02 | Brown Co | Process for recovering heat and chemicals |
| DE897513C (en) * | 1942-01-16 | 1953-11-23 | Hilding Olof Vidar Bergstroem | Process for the evaporation of pulp waste liquors |
| US2754897A (en) * | 1951-01-22 | 1956-07-17 | Ramen Torsten | Processes for concentrating liquids containing incrustation-forming substances |
| US2891843A (en) * | 1953-02-09 | 1959-06-23 | Minnesota & Ontario Paper Co | Chemical recovery process and apparatus |
| FR1112129A (en) * | 1953-11-19 | 1956-03-08 | Inventa Ag | Process for the preparation of lignin from black liquors |
| US3026240A (en) * | 1959-05-04 | 1962-03-20 | Babcock & Wilcox Co | Chemical recovery system |
| US3092535A (en) * | 1960-04-27 | 1963-06-04 | Smith Paper Mills Ltd Howard | Sulphite pulping process |
| NL273213A (en) * | 1961-01-05 | |||
| US3451765A (en) * | 1964-03-25 | 1969-06-24 | Frederick A Schleindl | Method of treating spent pulp liquor by adding gas-evolving metals thereto |
| CH552716A (en) * | 1972-03-06 | 1974-08-15 | Promotion Et D Exploit Ind De | PROCESS FOR OBTAINING CELLULOSE FROM LIGNO-CELLULOSIC RAW MATERIALS. |
| SE377348B (en) * | 1972-07-14 | 1975-06-30 | Mo Och Domsjoe Ab | |
| DE2506970C3 (en) * | 1975-02-19 | 1981-04-16 | Metallgesellschaft Ag, 6000 Frankfurt | Process for converting highly viscous waste pulp liquors into a pumpable state |
| CA1097465A (en) * | 1976-11-30 | 1981-03-17 | James R. Prough | Black liquor energy recovery |
| FI60041C (en) * | 1980-05-21 | 1981-11-10 | Ahlstroem Oy | FOERFARANDE FOER TILLVERKNING AV ALKALISK SULFITMASSA |
| FI64409C (en) * | 1981-06-01 | 1983-11-10 | Tampella Oy Ab | SAETT ATT STYRA FOERBRAENNINGEN AV EN TILL SIN KEMISKA KOMPOSITION VARIERANDE BRAENNLUT I SODAPANNAN |
| SE452482B (en) * | 1982-04-28 | 1987-11-30 | Sunds Defibrator | PROCEDURE FOR BATCH PREPARATION OF SULPHATE Pulp WITH HIGH DEGREE |
| SE8204266L (en) * | 1982-07-12 | 1984-01-13 | Korsnaes Marma Ab | PROCEDURE FOR SUBMISSION OF THE CHEMICAL LOSSES DURING MASS PREPARATION |
| US4470876A (en) * | 1982-07-22 | 1984-09-11 | Beaupre Marc F | Kraft overload recovery process |
| FI66035B (en) * | 1982-09-14 | 1984-04-30 | Rauma Repola Oy | FOERFARANDE FOER FOERBAETTRING AV AVDUNSTBARHET AV AVFALLSVAETSKA UPPSTAODD UNDER CELLULOSAFRAMSTAELLNINGSPROCESS |
| FI65375C (en) * | 1982-09-20 | 1984-05-10 | Ekono Oy | SAETT VID AOTERKOMPRESSIONSINDUNSTNING AV EN LOESNING |
| SE8400904L (en) * | 1984-02-20 | 1985-08-21 | Goetaverken Energy Syst Ab | METHOD AND DEVICE FOR REDUCING THE VISCOSITY OF BLACK LIQUID |
| JPS6183391A (en) * | 1984-09-26 | 1986-04-26 | 製紙技術研究組合 | Concentration of black liquor |
| SE8502807D0 (en) * | 1985-06-06 | 1985-06-06 | Ahlstroem Foeretagen | SET AND DEVICE DISABLE DEVICE |
-
1985
- 1985-11-29 FI FI854732A patent/FI75615C/en not_active IP Right Cessation
-
1986
- 1986-11-24 JP JP61506274A patent/JPS63502674A/en active Granted
- 1986-11-24 BR BR8607216A patent/BR8607216A/en not_active IP Right Cessation
- 1986-11-24 WO PCT/FI1986/000133 patent/WO1987003315A1/en active Application Filing
- 1986-11-27 CS CS868786A patent/CS273179B2/en unknown
- 1986-11-28 PL PL1986262650A patent/PL155015B1/en unknown
- 1986-11-28 PT PT83838A patent/PT83838B/en not_active IP Right Cessation
- 1986-11-28 FR FR868616691A patent/FR2593528B1/en not_active Expired - Fee Related
- 1986-11-28 CA CA000524062A patent/CA1288203C/en not_active Expired - Lifetime
-
1988
- 1988-05-25 SE SE8801948A patent/SE466756B/en not_active IP Right Cessation
- 1988-05-27 SU SU884355885A patent/SU1720498A3/en active
-
1989
- 1989-02-17 US US07/312,424 patent/US4929307A/en not_active Expired - Lifetime
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101580285A (en) * | 2009-04-01 | 2009-11-18 | 兰州节能环保工程有限责任公司 | Thermal cracking device for papermaking black liquor of non-wood material |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2593528A1 (en) | 1987-07-31 |
| FI854732A0 (en) | 1985-11-29 |
| US4929307A (en) | 1990-05-29 |
| PL155015B1 (en) | 1991-10-31 |
| BR8607216A (en) | 1988-11-01 |
| JPS63502674A (en) | 1988-10-06 |
| FR2593528B1 (en) | 1990-03-30 |
| SE8801948L (en) | 1988-05-25 |
| SE466756B (en) | 1992-03-30 |
| FI854732A (en) | 1987-05-30 |
| FI75615C (en) | 1991-08-26 |
| SE8801948D0 (en) | 1988-05-25 |
| PL262650A1 (en) | 1987-11-02 |
| CS868786A2 (en) | 1990-06-13 |
| JPH0248677B2 (en) | 1990-10-25 |
| PT83838A (en) | 1986-12-01 |
| WO1987003315A1 (en) | 1987-06-04 |
| PT83838B (en) | 1988-10-14 |
| CS273179B2 (en) | 1991-03-12 |
| FI75615B (en) | 1988-03-31 |
| SU1720498A3 (en) | 1992-03-15 |
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